Muffler



g- 11, 1959' L. M. MORRISH ET AL 2,899,007

MUFFLER Filed Sept. 19. 1955 NM IMML! United States Patent MUFFLER Leonard M. Morrish and Lloyd E. Muller, Flint, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application September 19, 1955, Serial No. 534,918

1 Claim. (Cl. 181-54) The invention relates to mufflers for engines and has particular relation to mufilers applicable for use in high speed, high powered, internal combustion engines for automotive and other purposes.

It is proposed to construct a light weight, durable and inexpensive mufiler that may be disposed in the limited space available beneath the floor in automotive vehicles as now constructed.

In the drawing:

Fig. 1 is a longitudinal sectional view of a mufiler embracing the invention;

Fig. 2 is a cross sectional view taken substantially in the plane of line 22 of Fig. 1 looking in the direction of the arrows thereon;

Fig. 3 is a cross sectional view taken substantially in the plane of line 33 of Fig. 1 looking in the direction of the arrows thereon; and

Fig. 4 is a fragmentary cross sectional view of one of the louvres forming a part of the acoustical coupling means employed in the structure disclosed by the preceding figures.

The mufller employed in practicing the invention comprises a casing 11 formed by a tubular outer wall 12 the ends of which are closed by end walls 13 and 14. The interior of the casing 11 is divided by partitions 15, 16, 17 18 and 19 to provide resonating chambers 21, 22, 23 and 24 and expansion chambers 26 and 27. An inlet conduit 28 extends into the casing 11 through end wall 13 and partitions 15, 16 and 17 and opens into the expansion chamber 27. An outlet conduit 29 extends through casing 11 from the expansion chamber 26 and through partitions 16, 17, 18 and 19 and end wall 14. Expansion chambers 26 and 27 communicate with one another through an intermediate conduit 31 extending through partitions 16 and 17 and disposed around and in spaced relation to the part of the outlet conduit 29 which extends through the resonating chamber 22. Flanges 30 are formed on the partitions 16 and 17 for supporting the intermediate conduit 31.

The resonating chamber 22 communicates with inlet conduit 28 through acoustical coupling means formed by louvred opening means 32 and an annular passage 33 formed within a tube 34 disposed about the inlet conduit 28 and extending through partitions and 16. The end of the tube 34 within resonating chamber 21 is closed by a flanged ring 36 between the end of the tube 34 and the conduit 28.

Disposed within the annular space between the intermediate tube 31 and the outlet conduit 29 is an inner casing 38 that is secured to outlet conduit 29 by flanged rings 39. The end of the inner casing 38 adjacent the partition 16 is supported by spaced tongues 35 that extend radially inwardly from the flange 30 on the partition 16. Rings 39 are spaced from one another to provide smaller resonating chambers 41 and 42 around the conduit 29 and within the inner casing 38. The resonating chambers 41 and 42 are acoustically coupled to the conduit 29 by louvred opening means 43 and 44. Secured about and ice in spaced relation to the outlet conduit 29 beyond the inner casing 38 is a coupling tube 46 that is spaced from the conduit 29 to provide an annular coupling passage 47. The coupling passage 47 communicates with the interior of the conduit 29 through louvred coupling means indicated at 48. Resonating chamber 24 also is connected to the interior of outlet conduit 29 through louvred opening means indicated at 49. The resonating chamber 21 may be connected to the expansion chamber 26 by a coupling tube 53. If desirable the tube 53 may be disposed in alignment with the outlet conduit 29.

The louvred opening means 32, 43, 44, 48 and 49 may be constructed in any suitable manner or as shown in Fig. 4. The numeral 51 indicates a louvred opening formed by slitting the metal of the conduits 28 and 29 and displacing therefrom the arcuate part indicated at 52. The louvred opening means all may be formed by forming a plurality of the openings indicated at 51.

The resonating chambers 21, 22, 23, 24, 41 and 42 all may be tuned to sounds emanating from the engine with which the muffler is employed, through the acoustical coupling means shown.

We claim:

A mufller for engines comprising an elongated casing, said casing having at least three spaced resonating chambers of relatively large volume and two expansion chambers therein, said large volume resonating chambers and said expansion chambers being formed by transverse partitions extending across said casing, the first of said expansion chambers lying between the first and second of said large volume resonating chambers, the second of said expansion chambers lying between the second and third of said large volume resonating chambers, an acoustic coupling tube projecting from the partition between said first of said large volume resonating chambers and said first expansion chamber into said first resonating chamber, an inlet conduit extending within said casing across said first and second large volume resonating chambers terminating within the second of said expansion chambers, said inlet conduit being surrounded by a concentric first acoustic coupling tube forming a first annular passage terminating in the second of said large volume resonating chambers, said inlet conduit being partially perforated to provide communication with said first annular passage, an outlet conduit extending within said casing and across said second and third of said large volume resonating chambers and in communication with said first expansion chamber, an imperforate intermediate conduit surrounding said outlet conduit and connecting said first and second expansion chambers through said second large volume resonating chamber, the portion of said outlet conduit within said intermediate conduit being perforated and surrounded by a radially spaced tubular member forming therewith at least one small volume resonating chamber, said tubular member continuing into a second acoustic coupling tube forming a second annular passage terminating in the third of said large volume resonating chambers and means acoustically connecting said outlet conduit with said second annular space.

References Cited in the file of this patent UNITED STATES PATENTS 2,125,449 Kingsley Aug. 2, 1938 2,160,332 Huber May 30, 1939 2,337,299 Noblitt et a1. Dec. 21, 1943 2,511,713 Hoyle et a1 June 13, 1950 2,661,073 Deremer Dec. 1, 1953 FOREIGN PATENTS I,

496,278 Canada Sept. 22, 1953 

